Image mosaics are created by merging multiple digital images. For example, a number of images taken inside an office building form a panoramic view of the inside of the office building. Each image may capture a different indoor area of the office building. The individual images of the different areas are merged together to form a comprehensive view of the entire area. For example, to image the inside of a large office building, hundreds of individual images may be required. The process of merging two or more individual images is referred to as “stitching,” and the location where two images meet is called a “seam.”
The images merged together to form the panoramic view of the inside of the office building are typically captured by several cameras positioned on a common platform. Each of the cameras is positioned on the common platform accordingly to cover a 360 degree field of view of the inside of the office building. Because each camera is positioned in a different location on the common platform, each camera has its own center of projection rather than having a single common center of projection. The distance between the common platform and the walls, floor, ceilings, and objects positioned inside the building is short such that the images generated by the several cameras of the inside of the office building are near-field images.
Stitching artifacts may be generated when near-field images that are captured from different cameras with different centers of projection are stitched together to form the panoramic view of the inside of the office building due to parallax. Parallax refers to a perceived shift of an imaged object against a background caused by the distance between apertures of each camera positioned on the common platform. Existing satellite and some airborne cameras do not have to account for parallax since both the focal length between the cameras and the object being imaged (e.g., the ground) is large enough such that the distance between apertures of each camera is negligible. When the focal length is decreased, such as in near-field imaging and also for airborne cameras in lower flying planes, such as those capturing images of a bird's eye view, stitching artifacts due to parallax becomes a greater issue.